Former Qantas chief Geoff Dixon has broken a near two year silence about the beleaguered national carrier to call for the complete abolition of the Qantas Sale Act and throw support to his successor Alan Joyce.

The Coalition government has a plan to abolish the Qantas Sale Act, but the the legislation which passed the lower house earlier this month is expected to be blocked in the Senate by Labor and the Greens. The act prevents a single entity from owning more than 25 per cent of the airline, and limits foreign airline ownership to 35 per cent.

Mr Dixon had a high profile falling out with his successor, Alan Joyce, in late 2012 over the airline's strategic direction and a push by a group of investors, including Mr Dixon, to take over the airline.

Speaking in Canberra on Wednesday, Mr Dixon initially declined to speak about Qantas, arguing he had not done so for about two years and “it is not time to break that duck now”.

But when pressed on the government's plan to lift foreign ownership restrictions on the airline and repeal sections of the Sale Act that mandate maintenance be performed in Australia, Mr Dixon said Mr Joyce and the airline's board should be “given the chance to get on with the job”.

“I personally think that the Qantas Sale Act should be abandoned totally, always have. I said it for eight years when I was running the company and I agree with exactly what Alan and the board are saying at the moment," he said.

And in a pointed barb directed at the union movement, Mr Dixon added that industrial relations had “always been a problem”.

Mr Dixon's surprising show of support for his successor come a day after Mr Joyce faced a grilling during a Senate hearing over his future at the airline from Labor senator Sam Dastyari.

Senator Dastyari honed in on Mr Joyce's tenure as chief executive, pointing out that Qantas' share price had fallen from $2.35 in December 2008 – when Mr Joyce took over – to $1.09 on Tuesday, while the airline's market capitalisation had fallen from about $4.5 billion to about $2.4 billion.

Mr Joyce said he had not spoken to each member of the board individually to test their support for his position because “it didn't work that way".

"Maybe it works that way in politics, but its doesn't work that way in the corporate world.”